/// <summary>
/// By reading the header on the provided stream this calculates the images format.
/// </summary>
/// <param name="stream">The image stream to read the header from.</param>
/// <param name="config">The configuration.</param>
/// <param name="format">The IImageFormat.</param>
/// <returns>The image format or null if none found.</returns>
private static IImageDecoder DiscoverDecoder(SpanUnmanagedArray <byte> stream, Configuration config, out IImageFormat format)
{
format = InternalDetectFormat(stream, config);
if (format != null)
{
return(config.FindDecoder(format));
}
return(null);
}
/// <summary>
/// By reading the header on the provided stream this calculates the images format.
/// </summary>
/// <param name="stream">The image stream to read the header from.</param>
/// <param name="config">The configuration.</param>
/// <returns>The mime type or null if none found.</returns>
private static IImageFormat InternalDetectFormat(SpanUnmanagedArray <byte> stream, Configuration config)
{
// This is probably a candidate for making into a public API in the future!
int maxHeaderSize = config.MaxHeaderSize;
if (maxHeaderSize <= 0)
{
return(null);
}
var header = stream.Slice(0, maxHeaderSize);
return(config.FormatDetectors.Select(x => x.DetectFormat(header)).LastOrDefault(x => x != null));
}
/// <summary>
/// Create a new instance of the <see cref="Image{TPixel}"/> class from the given stream.
/// </summary>
/// <param name="config">The configuration options.</param>
/// <param name="stream">The stream containing image information.</param>
/// <param name="format">the mime type of the decoded image.</param>
/// <exception cref="NotSupportedException">
/// Thrown if the stream is not readable nor seekable.
/// </exception>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <returns>A new <see cref="Image{TPixel}"/>.</returns>>
public static Image <TPixel> Load <TPixel>(Configuration config, SpanUnmanagedArray <byte> stream, out IImageFormat format)
where TPixel : struct, IPixel <TPixel>
{
config = config ?? Configuration.Default;
(Image <TPixel> img, IImageFormat format)data = Decode <TPixel>(stream, config);
format = data.format;
if (data.img != null)
{
return(data.img);
}
var stringBuilder = new StringBuilder();
stringBuilder.AppendLine("Image cannot be loaded. Available decoders:");
foreach (KeyValuePair <IImageFormat, IImageDecoder> val in config.ImageDecoders)
{
stringBuilder.AppendLine($" - {val.Key.Name} : {val.Value.GetType().Name}");
}
throw new NotSupportedException(stringBuilder.ToString());
}
/// <summary>
/// Create a new instance of the <see cref="Image{TPixel}"/> class from the given stream.
/// </summary>
/// <param name="config">The configuration options.</param>
/// <param name="stream">The stream containing image information.</param>
/// <exception cref="NotSupportedException">
/// Thrown if the stream is not readable nor seekable.
/// </exception>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <returns>A new <see cref="Image{TPixel}"/>.</returns>>
public static Image <TPixel> Load <TPixel>(Configuration config, SpanUnmanagedArray <byte> stream)
where TPixel : struct, IPixel <TPixel>
{
return(Load <TPixel>(config, stream, out var _));
}
/// <summary>
/// Create a new instance of the <see cref="Image{TPixel}"/> class from the given stream.
/// </summary>
/// <param name="stream">The stream containing image information.</param>
/// <exception cref="NotSupportedException">
/// Thrown if the stream is not readable nor seekable.
/// </exception>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <returns>A new <see cref="Image{TPixel}"/>.</returns>>
public static Image <TPixel> Load <TPixel>(SpanUnmanagedArray <byte> stream)
where TPixel : struct, IPixel <TPixel>
{
return(Load <TPixel>(null, stream));
}
/// <summary>
/// Create a new instance of the <see cref="Image{Rgba32}"/> class from the given stream.
/// </summary>
/// <param name="config">The config for the decoder.</param>
/// <param name="stream">The stream containing image information.</param>
/// <exception cref="NotSupportedException">
/// Thrown if the stream is not readable nor seekable.
/// </exception>
/// <returns>A new <see cref="Image{Rgba32}"/>.</returns>>
public static Image <Rgba32> Load(Configuration config, SpanUnmanagedArray <byte> stream) => Load <Rgba32>(config, stream);
/// <summary>
/// By reading the header on the provided stream this calculates the images mime type.
/// </summary>
/// <param name="config">The configuration.</param>
/// <param name="stream">The image stream to read the header from.</param>
/// <returns>The mime type or null if none found.</returns>
public static IImageFormat DetectFormat(Configuration config, SpanUnmanagedArray <byte> stream)
{
return(InternalDetectFormat(stream, config ?? Configuration.Default));
}
/// <summary>
/// By reading the header on the provided stream this calculates the images mime type.
/// </summary>
/// <param name="stream">The image stream to read the header from.</param>
/// <returns>The mime type or null if none found.</returns>
public static IImageFormat DetectFormat(SpanUnmanagedArray <byte> stream)
{
return(DetectFormat(null, stream));
}
